This proposal addresses itself to the relationship between arterial blood pressure, renal blood flow, and urine volume and composition. The nonfiltering kidney will be used to investigate autoregulatory mechanisms. The effect of pressure on autoregulation of renal blood flow and glomerular filtration rate will be assessed in normal and nonfiltering canine kidneys. The effect of vasodilators, pharmacologic blockade of angiotensin II, inhibition of prostaglandin synthetases and diuretics on autoregulation in these kidneys will be determined.